Laboratory experiments for studying Collisional Disruption in the Solar System Based on a Donald R. Davis’ article English...
Table of contents <ul><li>Why to study collisional disruptions ? </li></ul><ul><li>Types of collisional outcomes </li></ul...
Why to study collisional disruptions ? <ul><li>Moon formation caused by a collision between a Mars-size body and the Earth...
Type of collisional outcomes A question of velocity <ul><li>Slow velocity impact </li></ul><ul><ul><ul><li>Accretion </li>...
Fragmentation modes Question of velocity and target material <ul><li>Rock </li></ul><ul><ul><ul><li>Low velocity </li></ul...
Some definitions <ul><li>Fragmentation degree : f d  = M b /M o </li></ul><ul><ul><ul><li>M b  : Mass of the biggest fragm...
The experimental laws <ul><li>1st experimental law : f d  = K . Q -a </li></ul><ul><ul><li>Where K and a are empirically d...
Extrapolation to the Solar System <ul><li>Scale difficulties :  </li></ul><ul><ul><li>Asteroïds are 10 6  at 10 8  bigger ...
Conclusions <ul><li>Study of collisional disruptions </li></ul><ul><ul><li>Predict the consequences of an impact with the ...
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English presentation odoardi

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English presentation odoardi

  1. 1. Laboratory experiments for studying Collisional Disruption in the Solar System Based on a Donald R. Davis’ article English presentation Daniel Odoardi Monday, the 6th of December Master EFTIS IUFM de Nice - UNSA
  2. 2. Table of contents <ul><li>Why to study collisional disruptions ? </li></ul><ul><li>Types of collisional outcomes </li></ul><ul><li>Fragmentation modes </li></ul><ul><li>Experimental laws </li></ul><ul><li>Extrapolation to the Solar System </li></ul>
  3. 3. Why to study collisional disruptions ? <ul><li>Moon formation caused by a collision between a Mars-size body and the Earth </li></ul><ul><li>Extinction of the dinosaur (impact in the yucatan 65 million years ago) </li></ul><ul><li>More than 2000 collisions with a body of a mass greater than 1 kilogram per day </li></ul><ul><li>Anticipate the consequences of a collision between an asteroid and the Earth </li></ul><ul><li>Understand the Solar System formation </li></ul><ul><li>Study of the chondrites : the elementary bricks of the Solar System </li></ul><ul><li>Collisions between small bodies is the origin of planet formation </li></ul>
  4. 4. Type of collisional outcomes A question of velocity <ul><li>Slow velocity impact </li></ul><ul><ul><ul><li>Accretion </li></ul></ul></ul><ul><ul><ul><li>Inelastic rebound </li></ul></ul></ul><ul><li>High velocity impact </li></ul><ul><ul><ul><li>Cratering </li></ul></ul></ul><ul><ul><ul><li>Fragmentation </li></ul></ul></ul>
  5. 5. Fragmentation modes Question of velocity and target material <ul><li>Rock </li></ul><ul><ul><ul><li>Low velocity </li></ul></ul></ul><ul><ul><ul><li>High velocity </li></ul></ul></ul><ul><li>Ice </li></ul><ul><ul><ul><li>Low velocity </li></ul></ul></ul><ul><ul><ul><li>High vleocity </li></ul></ul></ul><ul><li>Iron </li></ul><ul><ul><ul><li>High velocity </li></ul></ul></ul>
  6. 6. Some definitions <ul><li>Fragmentation degree : f d = M b /M o </li></ul><ul><ul><ul><li>M b : Mass of the biggest fragment </li></ul></ul></ul><ul><ul><ul><li>M o : Mass of the original body </li></ul></ul></ul><ul><ul><ul><li>If f d < 0.5  Fragmentation </li></ul></ul></ul><ul><ul><ul><li>If f d > 0.5  Cratering </li></ul></ul></ul><ul><li>Specific energy : Q = E tot / mass </li></ul><ul><ul><ul><li>It is a kinetic energy </li></ul></ul></ul>
  7. 7. The experimental laws <ul><li>1st experimental law : f d = K . Q -a </li></ul><ul><ul><li>Where K and a are empirically determined </li></ul></ul><ul><li>2nd experimental law : N(>m) = (M b /m) b </li></ul><ul><li>N(>m) = number of fragments with a mass greather than m and b = 1/(1+f d ) </li></ul><ul><li>Actually, to use two power law gives better results </li></ul><ul><li>3rd experimental law : V(m) = V o .(m/M o ) -r </li></ul><ul><li>V o = V o (Q) and r ~ (1-b).4/9 </li></ul>
  8. 8. Extrapolation to the Solar System <ul><li>Scale difficulties : </li></ul><ul><ul><li>Asteroïds are 10 6 at 10 8 bigger than bodies studied in laboratories </li></ul></ul><ul><ul><li>Specific energy Q* needed to have fragmentation depends of the size of the body </li></ul></ul><ul><li>Solutions : </li></ul><ul><ul><li>Power law for take into account the mecanical effects  dominant for small bodies </li></ul></ul><ul><ul><li>Power law for take into account the gravitationnal effects  dominant for big bodies </li></ul></ul>
  9. 9. Conclusions <ul><li>Study of collisional disruptions </li></ul><ul><ul><li>Predict the consequences of an impact with the Earth </li></ul></ul><ul><ul><li>Understand the Solar System formation </li></ul></ul><ul><li>Different types of collisional outcomes </li></ul><ul><li>Different types of fragmentation modes </li></ul><ul><li>Tree experimental laws </li></ul><ul><li>Power laws for extrapolation to the Solar System </li></ul>
  10. 10. Thanks for your attention

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